Bump Salsa revision manually for non-Salsa updates

[lionel-]

Branched from #1314
Part of #1212

Removes a FIXME that I left for non-Salsa inputs, like console inputs and diagnostics config. These updates manually triggered diagnostics out-of-band, which had the issue that ongoing diagnostics did not get cancelled by a Salsa bump. The concurrent diagnostics could publish out of order, resulting in stale results.

It's actually easy to bump the revision manually, which both cancels in flight diagnostics and ensures ordering. That's because the synthetic write:

• Causes Salsa to trigger cancellation and park the caller until all readers are dropped
• Refreshes diagnostics automatically via the revision check at the end of the main loop.